1. Field of the Invention
The invention relates to an electrical soldering device, with a transformer disposed in a housing whose primary winding is connectible to an alternating current source, for instance through a cable with a plug to be connected into a socket, and whose secondary winding is connected to a loop-shaped, bent resistance wire which forms the soldering tip.
2. Description of the Related Art
Soldering devices of this general kind, usually referred to a soldering guns with reference to their pistol-like shape, have been heretofore known. When the primary winding of the transformer is connected to an A.C. source, such as a conventional A.C. mains providing a voltage of 110V (220V) and a frequency of 60 Hz (50 Hz), a current of considerable current strength flows in the resistance wire which forms the soldering tip. Due to the internal resistance of the wire, the resistance wire is quickly heated to a temperature which causes the solder metal to melt when it comes into contact with the resistance wire.
Such soldering devices may also be used for desoldering. In that case, a desoldering tip according to Austrian Patent AT-PS 374 392 may be provided for instance.
One of the drawbacks of the prior art electrical soldering devices is their relatively great weight caused by the required transformer in the housing. The weight of the transformer is thereby mainly determined by its core, which is formed from transformer metal sheets. The relatively great weight of those soldering devices causes the hand of the operator to tire quickly, making it increasingly difficult during extended soldering to accurately guide the soldering tip at a soldering location. This is particularly disadvantageous in the case of small, closely adjacent soldering locations.
In an effort to reduce the weight of such soldering devices, it has heretofore been proposed to connect a frequency converter into the supply line. The converter is laid out such that the transformer is supplied with a frequency which is increased relative to the frequency of the alternating current source (60/50 Hz), in particular to a frequency in the kilohertz range. While this makes it possible to dimension the transformer core smaller while maintaining its power capacity--and thus reduce its weight--this still does not lead to an optimal configuration of the soldering device. The primary reason for that is found in the fact that the transformer of that prior art configuration still exhibits considerable dimensions. Furthermore, those prior art dimensions are yet enlarged when the transformer is provided with the usual tertiary winding for operating a control lamp.